Conditional termination of RSTD measurements

ABSTRACT

Methods and device for use in a wireless device of reporting positioning measurements comprises receiving network assistance information from a network node. The network assistance information is for assisting the wireless device in performing Observed Time Difference Of Arrival (OTDOA), and comprises: a list of reference cells; a list of neighbor cells; and a rule for terminating Reference Signal Time Difference (RSTD) measurements. The method further comprises performing RSTD measurement between a cell in the reference cell list and a cell in the neighbor cell list. Upon determining the RSTD measurement satisfies the rule for terminating RSTD measurements, the method includes reporting the RSTD measurements to the network node. Upon determining the RSTD measurement does not satisfy the rule for terminating RSTD measurements, performing another RSTD measurement between the cell in the reference cell list and a cell in the neighbor cell list.

PRIORITY

This application is a continuation, under 35 U.S.C. § 120 of U.S. patentapplication Ser. No. 16/347,250 filed on May 3, 2019, which is a U.S.National Stage Filing under 35 U.S.C. § 371 of International PatentApplication Serial No. PCT/IB2017/56885 filed Nov. 3, 2017 and entitled“Conditional Termination of RSTD Measurements” which claims priority toU.S. Provisional Patent Application No. 62/417,962 filed Nov. 4, 2016both of which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

Certain embodiments of the present disclosure relate, in general, towireless communications and, more particularly, to conditionaltermination of reference signal time difference (RSTD) measurements.Certain embodiments may relate to the technology areas of Internet ofThings (IoT), Narrowband IoT (NB-IoT), Machine-Type Communications(MTC), Reference Signal Time Difference, Observed Time Difference ofArrival (OTDOA), and/or other suitable technology areas.

INTRODUCTION

The Internet of Things (IoT) is a vision for the future world whereeverything that can benefit from a connection will be connected.Cellular technologies are being developed or evolved to play anindispensable role in the IoT world, particularly the machine typecommunication (MTC). MTC is characterized by lower demands on data ratesthan, for example, mobile broadband, but with higher requirements on,for example, low cost device design, better coverage, and an ability tooperate for years on batteries without charging or replacing thebatteries. To meet the IoT design objectives, the Third GenerationPartnership Project (3GPP) has standardized Narrowband IoT (NB-IoT) inlong term evolution (LTE) Release 13 to include a system bandwidth of180 kHz and targets improved coverage, long battery life, low complexitycommunication design, and network capacity that is sufficient forsupporting a massive number of devices.

To further increase the market impact of further enhanced MTC andNB-IoT, improving narrowband support for positioning can be a key aspectof both of these devices in Release 14. The enhancements will maintainthe ultra-low cost and complexity of these UE where appropriate, as wellas the coverage and capacity of the network.

LTE Release 13 also includes UE category M1, which addresses moredemanding MTC applications. UE category M1 is associated with a maximumchannel bandwidth of 6 physical resource blocks (PRBs) (corresponding to1.08 MHz excluding guard bands or 1.4 MHz including guard bands), whichcan be compared to 1 PRB for NB-IoT UEs or 100 PRBs for higher LTE UEcategories. Furthermore, 3GPP includes a LTE Release 14 work item onfurther enhanced MTC (FeMTC), where a UE type based on UE category M1with a maximum channel bandwidth of approximately 25 PRBs (correspondingto 4.5 MHz excluding guard bands and 5 MHz including guard bands) isspecified to address even more demanding applications. In the FeMTC workitem, Observed Time Difference of Arrival (OTDOA) improvements withrespect to positioning accuracy, user equipment (UE) complexity andpower consumption for these (6-PRB and 25-PRB) UEs may be considered forstandardization.

Location-based services and emergency call positioning drive thedevelopment of positioning in wireless networks. Positioning support in3GPP LTE is included in Release 9. This enables operators to retrieveposition information for location-based services and to meet regulatoryemergency call positioning requirements. Positioning in LTE is supportedby the architecture in FIG. 1.

FIG. 1 is a block diagram illustrating the architecture of an exampleLTE system. In the illustrated example, direct interaction between a UEand a location server (e.g., Evolved Serving Mobile Location Centre(E-SMLC)) is via the LTE Positioning Protocol (LPP). Moreover, there arealso interactions between the location server and the eNodeB via theLPPa protocol, to some extent supported by interactions between theeNodeB and the UE via the Radio Resource Control (RRC) protocol. Thefollowing positioning techniques are considered in LTE: (a) EnhancedCell ID—cell ID information to associate the UE to the serving area of aserving cell, and then additional information to determine a finergranularity position; (b) Assisted Global Navigation Satellite System(GNSS)—GNSS information retrieved by the UE, supported by assistanceinformation provided to the UE from E-SMLC; (c) OTDOA—a UE estimates thetime difference of reference signals from different base stations andsends to the E-SMLC for multilateration; and (d) Uplink Time Differenceof Arrival (UTDOA)—a UE is requested to transmit a specific waveformthat is detected by multiple location measurement units (e.g., an eNB)at known positions, and the measurements are forwarded to E-SMLC formultilateration.

OTDOA is included in 3GPP release 9 as a downlink (DL) positioningmethod. As illustrated in FIG. 2, OTDOA in LTE is based on the devicemeasuring the time of arrival (TOA) of signals received from eNBs.

FIG. 2 illustrates OTDOA with three network nodes and a UE. The UEmeasures the relative difference between the reference cell (e.g., t1 ateNB1) and another specific cell (e.g., t2 at eNB2 or t3 at eNB3),defined as reference signal time difference (RSTD) measurement. Everysuch RSTD determines a hyperbola, and the intersecting point of thehyperbolas represents the device position. In the illustrated example,the reference cell is selected by the device and the RSTD measurementcan be performed on an intra-frequency cell (reference cell/neighborcell are on the same carrier frequency as the serving cell) orinter-frequency cell (at least one of reference cell/neighbor cell is onthe different carrier frequency from the serving cell).

OTDOA is the supported method for FeMTC UEs, and may support positioningfor NB-IoT. In conventional OTDOA, the UE conducts a set of RSTDmeasurements as requested from the location server via LPP. The time-tofix parameter denotes the time from when a UE is configured to measurethe RSTDs until the RSTD result report is sent.

SUMMARY

Particular problems exist with techniques for determining the positionof narrowband Internet of Things (NB-IoT) user equipment (UEs). Forexample, while Observed Time Difference of Arrival (OTDOA) may be apositioning method for NB-IoT UEs, the measurements and signalingrequired for OTDOA adds extra overhead to these low power and lowcomplexity devices. Computing the reference signal time differencebetween two cells requires processing effort for the UE. Thus, themeasurement process should be minimized as much as possible to maintainthe low-cost, power and complexity of these devices. This may beimportant in a dense cell deployment where a device could drain itsbattery by measuring on too many cells. Certain embodiments of thepresent disclosure may provide solutions to these and other problems.

Particular embodiments minimize the number of reference signal timedifference (RSTD) measurements performed by the IoT-UE to enable a lesscostly positioning estimation procedure for NB-IoT devices. The networkcan assist the UE in the number of required RSTD measurements andprovide a rule to determine when the device may terminate the RSTDmeasurement.

Some general steps performed by a UE include the following. Step 1:Receive a pre-defined/conditional rule for measurement terminationtogether with other OTDOA assistance information including the list ofreference and neighbor cells. Step 2: Perform RSTD measurement of twocells in the lists provided in Step 1. Step 3: Determine RSTD quality ofthe measured RSTD in Step 2. Step 4: If a termination criterion isreached according to the pre-defined rule sent in Step 1 go to 5, elsego to step 2. Step 5: Report the set of RSTD measurements and theirquality to the network node. Step 5.a In some embodiments, report thefulfilled termination condition.

Some general steps performed by a network node include the following.Step 1: Send a pre-defined/conditional rule for measurement terminationtogether with other OTDOA assistance information including the list ofreference and neighbor cells to the device. Step 2: Receive a set ofRSTD measurements and their quality from the device.

According to some embodiments, a method for use in a wireless device ofreporting positioning measurements comprises receiving networkassistance information from a network node. The network assistanceinformation is for assisting the wireless device in performing ObservedTime Difference of Arrival (OTDOA). The network assistance informationcomprises: a list of reference cells; a list of neighbor cells; and arule for terminating Reference Signal Time Difference (RSTD)measurements. The method further comprises performing RSTD measurementbetween a cell in the reference cell list and a cell in the neighborcell list. Upon determining the RSTD measurement satisfies the rule forterminating RSTD measurements, the method further comprises reportingthe RSTD measurements to the network node. Upon determining the RSTDmeasurement does not satisfy the rule for terminating RSTD measurementsthe method further comprises performing another RSTD measurement betweenthe cell in the reference cell list and a cell in the neighbor celllist.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least apre-determined number (N) of RSTD measurements having a least apre-determined quality (X). The pre-determined number (N) may be lessthan fifteen.

In particular embodiments, reporting the RSTD measurements to thenetwork node includes reporting a quality of the RSTD measurementsand/or an indication that the rule for terminating RSTD measurements wassatisfied.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least a firstpre-determined number (N1) of RSTD measurements having a least a firstpre-determined quality (X1) or at least a second pre-determined number(N2) of RSTD measurements having a least a second pre-determined quality(X2).

According to some embodiments, a wireless device is capable of reportingpositioning measurements. The wireless device comprises processingcircuitry operable to receive network assistance information from anetwork node. The network assistance information is for assisting thewireless device in performing OTDOA. The network assistance informationcomprises: a list of reference cells; a list of neighbor cells; and arule for terminating RSTD measurements. The processing circuitry isfurther operable to perform RSTD measurement between a cell in thereference cell list and a cell in the neighbor cell list. When theprocessing circuitry determines the RSTD measurement satisfies the rulefor terminating RSTD measurements, the processing circuitry is furtheroperable to report the RSTD measurements to the network node. When theprocessing circuitry determines the RSTD measurement does not satisfythe rule for terminating RSTD measurements, the processing circuitry isfurther operable to perform another RSTD measurement between the cell inthe reference cell list and a cell in the neighbor cell list.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least apre-determined number (N) of RSTD measurements having a least apre-determined quality (X). The pre-determined number (N) may be lessthan fifteen.

In particular embodiments, the report to the network node includes aquality of the RSTD measurements and/or an indication whether the rulefor terminating RSTD measurements was satisfied.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least a firstpre-determined number (N1) of RSTD measurements having a least a firstpre-determined quality (X1) or at least a second pre-determined number(N2) of RSTD measurements having a least a second pre-determined quality(X2).

According to some embodiments, a method for use in a network node ofproviding network assistance for positioning measurements comprisestransmitting network assistance information to a wireless device. Thenetwork assistance information is for assisting the wireless device inperforming OTDOA. The network assistance information comprises: a listof reference cells; a list of neighbor cells; and a rule for terminatingReference Signal Time Difference (RSTD) measurements. The method furthercomprises receiving a report that provides the RSTD measurements fromthe wireless device.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least apre-determined number (N) of RSTD measurements having a least apre-determined quality (X). The pre-determined number (N) may be lessthan fifteen.

In particular embodiments, the report includes a quality of the RSTDmeasurements and/or an indication that the rule for terminating RSTDmeasurements was satisfied.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least a firstpre-determined number (N1) of RSTD measurements having a least a firstpre-determined quality (X1) or at least a second pre-determined number(N2) of RSTD measurements having a least a second pre-determined quality(X2).

According to some embodiments, a network node is capable of providingnetwork assistance for positioning measurements. The network nodecomprises processing circuitry operable to transmit network assistanceinformation to a wireless device. The network assistance information isfor assisting the wireless device in performing OTDOA. The networkassistance information comprises: a list of reference cells; a list ofneighbor cells; and a rule for terminating RSTD measurements. Theprocessing circuitry is further operable to receive a report thatprovides the RSTD measurements from the wireless device.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least apre-determined number (N) of RSTD measurements having a least apre-determined quality (X). The pre-determined number (N) may be lessthan fifteen.

In particular embodiments, the report includes a quality of the RSTDmeasurements and/or an indication of whether the rule for terminatingRSTD measurements was satisfied.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least a firstpre-determined number (N1) of RSTD measurements having a least a firstpre-determined quality (X1) or at least a second pre-determined number(N2) of RSTD measurements having a least a second pre-determined quality(X2).

According to some embodiments, a wireless device is capable of reportingpositioning measurements. The wireless device comprises a receivingmodule, a measuring module, and a reporting module. The receiving moduleis operable to receive network assistance information from a networknode. The network assistance information is for assisting the wirelessdevice in performing OTDOA. The network assistance informationcomprises: a list of reference cells; a list of neighbor cells; and arule for terminating RSTD measurements. The measuring module is operableto perform RSTD measurement between a cell in the reference cell listand a cell in the neighbor cell list. When the processing circuitrydetermines the RSTD measurement satisfies the rule for terminating RSTDmeasurements, the reporting module is operable to report the RSTDmeasurements to the network node. When the processing circuitrydetermines the RSTD measurement does not satisfy the rule forterminating RSTD measurements, the measuring module is operable toperform another RSTD measurement between the cell in the reference celllist and a cell in the neighbor cell list.

According to some embodiments, a network node is capable of providingnetwork assistance for positioning measurements. The network nodecomprises a transmitting module and a receiving module. The transmittingmodule is operable to transmit network assistance information to awireless device. The network assistance information is for assisting thewireless device in performing OTDOA. The network assistance informationcomprises: a list of reference cells; a list of neighbor cells; and arule for terminating RSTD measurements. The receiving module is operableto receive a report that provides the RSTD measurements from thewireless device.

Also disclosed is a computer program product. The computer programproduct comprises instructions stored on non-transient computer-readablemedia which, when executed by a processor, perform the steps of:receiving network assistance information from a network node; andperforming RSTD measurement between a cell in a reference cell list anda cell in a neighbor cell list. Upon determining the RSTD measurementsatisfies the rule for terminating RSTD measurements, the instructionsfurther perform the step of reporting the RSTD measurements to thenetwork node. Upon determining the RSTD measurement does not satisfy therule for terminating RSTD measurements, the instructions further performthe step of performing another RSTD measurement between the cell in thereference cell list and a cell in the neighbor cell list.

Another computer program product comprises instructions stored onnon-transient computer-readable media which, when executed by aprocessor, perform the steps of: transmitting network assistanceinformation to a wireless device; and receiving a report that providesthe RSTD measurements from the wireless device.

Certain embodiments of the present disclosure may provide one or moretechnical advantages. For example, some embodiments include assisting awireless device to terminate a RSTD measurement after the wirelessdevice performs enough measurements. An another example, an advantage ofcertain embodiments includes avoiding unnecessary measurements by thewireless device. As another example, a technical advantage of certainembodiments includes minimizing the processing effort and powerconsumption at the device side. As yet another example, a technicaladvantage of certain embodiments includes reducing the overall overheardof OTDOA positioning method for IoT devices. As a further example, atechnical advantage of certain embodiments includes addingconfigurability at the location server to trade-off between positioningaccuracy and IoT device power consumption, e.g., because some deviceshave low positioning accuracy requirements. As a final example, atechnical advantage of certain embodiments includes adding theconfigurability to trade-off between time-to-fix and positioningaccuracy, a more restrictive termination criterion will lead to ashorter time-to-fix. Certain embodiments may have none, some, or all ofthe recited advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the embodiments and their featuresand advantages, reference is now made to the following description,taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating the architecture of an exampleLTE system;

FIG. 2 illustrates OTDOA with three network nodes and a UE;

FIG. 3 is a block diagram illustrating an example wireless network,according to a particular embodiment;

FIG. 4 is a flow diagram of an example method in a user equipment,according to some embodiments;

FIG. 5 is a flow diagram of an example method in a network node,according to some embodiments;

FIG. 6A is a block diagram illustrating an example embodiment of awireless device;

FIG. 6B is a block diagram illustrating example components of a wirelessdevice;

FIG. 7 is a block diagram illustrating an example embodiment of a radionetwork node; and

FIG. 8A is a block diagram illustrating an example embodiment of anetwork node; and

FIG. 8B is a block diagram illustrating example components of a networknode.

DETAILED DESCRIPTION

Particular embodiments disclosed herein assist Internet of Things (IoT)devices (e.g., narrowband IoT (NB-IoT) devices) to terminate a referencesignal time difference (RSTD) measurement procedure early if adequatemeasurement is available. Assisting the IoT devices may avoidperformance of unnecessary measurements by the device.

One potential advantage of using Observed Time Difference of Arrival(OTDOA) as the positioning method for IoT devices is preserving thelegacy signaling procedure for these devices as it was for legacy longterm evolution (LTE) user equipment (UEs). LTE uses LTE positioningprotocol (LPP) signaling between an evolved-serving mobile locationcenter (E-SMLC) to the UE, which provides OTDOA network assistanceinformation. The signaling can be useful for IoT devices considering thelimited capability and power consumption of IoT devices. Therefore,advantages may be realized reusing LTE signaling for IoT devices, andimprovements may be realized by tailoring the content of the signalingto the capabilities of the IoT devices.

As an example, in certain embodiments, the network node (i.e., E-SMLC)provides the NB-IoT UE with a list of potential reference cell andneighbor cells to be used for RSTD measurements. For each of theselists, the E-SMLC provides a set of information including the physicalcell ID, the global cell ID, the positioning reference signal (PRS)info, etc. The network node may also provide the expected RSTDmeasurement and the expected RSTD uncertainty measurement, which can beuseful to the UE.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to implement such feature, structure, orcharacteristic in connection with other embodiments, whether or notexplicitly described.

Generally, all terms used herein are to be interpreted according totheir ordinary meaning in the technical field, unless explicitly definedotherwise herein. All references to “a/an/the element, apparatus,component, means, step, etc.” are to be interpreted openly as referringto at least one instance of the element, apparatus, component, means,step, etc., unless explicitly stated otherwise. The steps of any methoddisclosed herein do not have to be performed in the exact orderdisclosed, unless explicitly stated.

Particular embodiments are described with reference to FIGS. 3-8B of thedrawings, like numerals being used for like and corresponding parts ofthe various drawings. LTE and NR are used throughout this disclosure asexample cellular systems, but the ideas presented herein may apply toother wireless communication systems as well.

FIG. 3 is a block diagram illustrating an example wireless network,according to a particular embodiment. Wireless network 100 includes oneor more wireless devices 110 (such as mobile phones, smart phones,laptop computers, tablet computers, MTC devices, or any other devicesthat can provide wireless communication) and a plurality of networknodes 120 (such as base stations or eNodeBs) Network node 120 servescoverage area 115 (also referred to as cell 115).

In general, wireless devices 110 that are within coverage of radionetwork node 120 (e.g., within cell 115 served by network node 120)communicate with radio network node 120 by transmitting and receivingwireless signals 130. For example, wireless devices 110 and radionetwork node 120 may communicate wireless signals 130 containing voicetraffic, data traffic, and/or control signals. A network node 120communicating voice traffic, data traffic, and/or control signals towireless device 110 may be referred to as a serving network node 120 forthe wireless device 110.

In some embodiments, wireless device 110 may be referred to by thenon-limiting term “UE.” A UE may include any type of wireless devicecapable of communicating with a network node or another UE over radiosignals. The UE may comprise radio communication device, target device,device to device (D2D) UE, machine type UE or UE capable of machine tomachine communication (M2M), a sensor equipped with UE, iPAD, Tablet,mobile terminals, smart phone, laptop embedded equipped (LEE), laptopmounted equipment (LME), USB dongles, Customer Premises Equipment (CPE),etc.

In some embodiments, network node 120 may include any type of networknode such as a base station, radio base station, base transceiverstation, base station controller, network controller, evolved Node B(eNB), Node B, multi-RAT base station, Multi-cell/multicast CoordinationEntity (MCE), relay node, access point, radio access point, Remote RadioUnit (RRU) Remote Radio Head (RRH), a core network node (e.g., MME, SONnode, a coordinating node, etc.), or even an external node (e.g., 3rdparty node, a node external to the current network), etc.

Wireless signals 130 may include both downlink transmissions (from radionetwork node 120 to wireless devices 110) and uplink transmissions (fromwireless devices 110 to radio network node 120).

Each network node 120 may have a single transmitter or multipletransmitters for transmitting wireless signals 130 to wireless devices110. In some embodiments, network node 120 may comprise a multi-inputmulti-output (MIMO) system. Similarly, each wireless device 110 may havea single receiver or multiple receivers for receiving signals 130 fromnetwork nodes 120.

Network 100 may include carrier aggregation. For example, wirelessdevice 110 may be served by both network node 120 a and 120 b andcommunicate wireless signals 130 with both network node 120 a and 120 b.

In certain embodiments, network nodes 125 may interface with a radionetwork controller (RNC). The radio network controller may controlnetwork nodes 120 and may provide certain radio resource managementfunctions, mobility management functions, and/or other suitablefunctions. In certain embodiments, the functions of the radio networkcontroller may be included in network node 120. The radio networkcontroller may interface with a core network node (CN), such as corenetwork node 320.

In certain embodiments, the radio network controller may interface withcore network node 320 via an interconnecting wired or wireless network.The interconnecting network may refer to any interconnecting systemcapable of transmitting audio, video, signals, data, messages, or anycombination of the preceding. The interconnecting network may includeall or a portion of a public switched telephone network (PSTN), a publicor private data network, a local area network (LAN), a metropolitan areanetwork (MAN), a wide area network (WAN), a local, regional, or globalcommunication or computer network such as the Internet, a wireline orwireless network, an enterprise intranet, or any other suitablecommunication link, including combinations thereof.

In some embodiments, core network node 320 may manage the establishmentof communication sessions and various other functionalities for wirelessdevices 110. Examples of core network node 320 may include mobileswitching center (MSC), mobility management entity (MME), servinggateway (SGW), packet data network gateway (PGW), operation andmaintenance (O&M), operations support system (OSS), SON, positioningnode (e.g., Enhanced Serving Mobile Location Center, (E-SMLC)), MDTnode, etc. Wireless devices 110 may exchange certain signals with corenetwork node 320 using the non-access stratum layer. In non-accessstratum signaling, signals between wireless devices 110 and core networknode 320 may be transparently passed through the radio access network.In certain embodiments, network nodes 120 may interface with one or morenetwork nodes 120 over an internode interface, such as, for example, anX2 interface.

In particular embodiments, core network node 320 may perform positioningfor a wireless device, such as wireless device 110. Core network node320 may transmit positioning reference signals (PRS) and positioningassistance information to wireless device 110. Core network node 320 mayreceive positioning measurements from wireless device 110.

In some embodiments, wireless device 110 may report positioningmeasurements. Wireless device 110 may receive network assistanceinformation from a network node, such as core network node 320. Thenetwork assistance information is for assisting wireless device 110 inperforming OTDOA. The network assistance information comprises: a listof reference cells; a list of neighbor cells; and a rule for terminatingRSTD measurements.

In some embodiments, wireless device 110 may use the network assistanceinformation to perform RSTD measurement between a cell in the referencecell list and a cell in the neighbor cell list. When wireless device 110determines the RSTD measurement satisfies the rule for terminating RSTDmeasurements, wireless device 110 may report the RSTD measurements tothe network node. When wireless device 110 determines the RSTDmeasurement does not satisfy the rule for terminating RSTD measurements,wireless device 110 may perform another RSTD measurement between thecell in the reference cell list and a cell in the neighbor cell list.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least apre-determined number (N) of RSTD measurements having a least apre-determined quality (X). The pre-determined number (N) may be lessthan fifteen.

In particular embodiments, the report to the network node includes aquality of the RSTD measurements and/or an indication whether the rulefor terminating RSTD measurements was satisfied.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least a firstpre-determined number (N1) of RSTD measurements having a least a firstpre-determined quality (X1) or at least a second pre-determined number(N2) of RSTD measurements having a least a second pre-determined quality(X2). Additional details are described below with respect to FIGS. 4 and5.

In wireless network 100, each radio network node 120 may use anysuitable radio access technology, such as long term evolution (LTE),LTE-Advanced, NR, UMTS, HSPA, GSM, cdma2000, WiMax, WiFi, and/or othersuitable radio access technology. Wireless network 100 may include anysuitable combination of one or more radio access technologies. Forpurposes of example, various embodiments may be described within thecontext of certain radio access technologies. However, the scope of thedisclosure is not limited to the examples and other embodiments coulduse different radio access technologies.

As described above, embodiments of a wireless network may include one ormore wireless devices and one or more different types of radio networknodes capable of communicating with the wireless devices. The networkmay also include any additional elements suitable to supportcommunication between wireless devices or between a wireless device andanother communication device (such as a landline telephone). A wirelessdevice may include any suitable combination of hardware and/or software.For example, in particular embodiments, a wireless device, such aswireless device 110, may include the components described below withrespect to FIG. 6A. Similarly, a radio network node may include anysuitable combination of hardware and/or software. For example, inparticular embodiments, a network node, such as network node 120, mayinclude the components described below with respect to FIG. 7. A corenetwork node may include any suitable combination of hardware and/orsoftware. For example, in particular embodiments, a core network node,such as core network node 320, may include the components describedbelow with respect to FIG. 8A.

Particular embodiments include response time termination. IoT devicesmay aggregate a downlink reference signal (e.g., positioning referencesignal (PRS)) for several/many occasions (repetitions) to achieve anacceptable positioning estimation. Aggregating the downlink referencesignal impacts the response time. Thus, in particular embodiments thenetwork node provides network assistance information to the UE. Thenetwork assistance information enables the UE to optimize performanceregarding the response time. The assistance may also minimize thecomplexity and power consumption of the UE. In one embodiment, thelegacy response time can be sub-divided into more numbers to assist theUE in prioritizing the RSTD measurement performance, meaning that theresponse time can be modified to also include time to measure N cells.

Some embodiments include a predefined rule for measurement termination.In conventional positioning procedures, the UE reports fifteen RSTDsassuming that the signal to interference-plus-noise ratio (SINR) isabove a threshold. To further assist an NB-IoT UE, and to avoidunnecessary measurement at the UE, in particular embodiments thelocation server provides the UE with the option that if N RSTDs withquality X have been measured, then the UE is allowed to report the RSTDmeasurement, and the UE does not continue with further measurements. Nand X may be configured via a measurement instruction. In someembodiments, it may be sufficient to do the positioning estimation witha fewer number of RSTDs if the RSTDs have adequate RSTD quality.

In some embodiments, a location server provides a UE with the optionthat if N RSTDs with quality X have been measured, then the UE isallowed to report the RSTD measurement, and the UE does not continuewith further measurements. The quality of RSTD measurement(rstd-Quality) may be defined based on error-Resolution, error-Value anderror-NumSamples, as described in Table 1.

TABLE 1 List of higher-layer result parameters. Description Symbol UnitReference Reference signal time difference measured at the UE Δt_(i)T_(s) 5.1.12 antenna connector to be obtained in RRC_CONNECTED RSTDreport map state (intra- and inter-frequency) and requires [1], 9.1.10.3compensation of potential bandwidth- or band dependent group delays (LPPreporting: rstd) Δt_(i) = t_(i) − T_(REF) Measurement range: −16384, . .. , 16383 Reportable range: −15391, . . . , 15391 (LPP: rstd-Quality)6.5.1.2 error-Resolution, bit string (2) error = X * R to Values: 5, 10,20, 30 meters (X + 1) * R − 1 meters, error-Value, bit string (5) whereX is given by Values: 0, . . . , 31 error-Value and R byerror-NumSamples, bit string (3) error-Resolution. Value: 0 (i.e., notthe baseline metrics) Note: Not the baseline metrics shall he reportedby which the UE can derive previous two fields based on e.g., SINR.Moreover we avoid disclosing information about how we derive the RSTDestimates.

In some embodiments, the choice of X by the location server is based on,but not limited to, the following: (a) error-Value; (b) error-Valuetimes error-Resolution; (c) SINR; (d) cross-correlation characteristicsof the estimated channels used for forming the RSTDs; and (e) anordering rule in the neighbor list. As an example, A UE may measure SINRand the choice of N and X may be as follows: (N, X)={(12, −14 dB), (10,−13 dB), (8, −12 dB), (6, −11 dB), (5, −10 dB)}

In particular embodiments, the IoT device performs RSTD measurementsbased on the assistance information sent by the location server. The UEmay report both the RSTD and RSTD quality to the E-SMILC. The RSTDquality is according to the estimated RSTD measurement sent by thelocation server. If the IoT device has terminated the RSTD measurementprocedure according to one of the conditional termination criteria sentby the network as the assistance data, the IoT device can optionallyreport the condition used together with the RSTD measurements.

Some embodiments may include signaling support via LPP. An example isgiven below.

-- ASN1START CommonIEsRequestLocationInformation ::= SEQUENCE {locationInformationType LocationInformationType,  triggeredReportingTriggeredReportingCriteria OPTIONAL, -- Cond ECID periodicalReporting PeriodicalReportingCriteria OPTIONAL, -- Need ON  additionalInformation AdditionalInformation OPTIONAL, -- Need ON qos  QoS OPTIONAL, -- NeedON  environment  Environment OPTIONAL, -- Need ONlocationCoordinateTypes  LocationCoordinateTypes OPTIONAL, -- Need ON velocityTypes  VelocityTypes OPTIONAL, -- Need ON ... }LocationInformationType ::= ENUMERATED { locationEstimateRequired,locationMeasurementsRequired, locationEstimatePreferred,locationMeasurementsPreferred, ... } PeriodicalReportingCriteria ::= SEQUENCE { reportingAmount ENUMERATED {  ra1, ra2, ra4, ra8, ra16,ra32,  ra64, ra-Infinity  } DEFAULT ra-Infinity, reportingIntervalENUMERATED {  noPeriodicalReporting, ri0-25,   ri0-5, ri1, ri2, ri4,ri8, ri16, ri32, ri64  } } TriggeredReportingCriteria ::= SEQUENCE {cellchange BOOLEAN, reportingDuration ReportingDuration, ... }ReportingDuration ::= INTEGER (0..255) AdditionalInformation ::=ENUMERATED { onlyReturnInformationRequested,mayReturnAditionalInformation, ... } QoS ::= SEQUENCE { horizontalAccuracy HorizontalAccuracy OPTIONAL, -- Need ONverticalCoordinateRequest BOOLEAN,  verticalAccuracy VerticalAccuracyOPTIONAL, -- Need ON  responseTime ResponseTime OPTIONAL, -- Need ONvelocityRequest   BOOLEAN, [[ adequatePos-r14  AdequatePos-r14OPTIONAL, -- Need ON ]] ... } HorizontalAccuracy ::= SEQUENCE { accuracyINTEGER(0..127), confidence INTEGER(0..100), ... } VerticalAccuracy ::=SEQUENCE { accuracy INTEGER(0..127), confidence INTEGER(0..100), ... }ResponseTime ::= SEQUENCE { time  INTEGER (1..128), ..., [[responseTimeEarlyFix-r12  INTEGER (1..128)  OPTIONAL  -- Need ON ]] }AdequatePos-r14 ::= SEQUENCE { minNoOfCells  INTEGER (1..16),minMeasQuality OTDOA-MeasQuality OPTIONAL -- Need ON, ... } Environment::= ENUMERATED { badArea, notBadArea, mixedArea, ... } -- ASN1STOP

Particular embodiments include methods in a wireless device and anetwork node. Examples are illustrated in FIGS. 4 and 5, respectively.

FIG. 4 is a flow diagram of an example method in a user equipment,according to some embodiments. Method 400 includes steps for reportingpositioning measurements. In particular embodiments, one or more stepsof FIG. 4 may be performed by wireless device 110 of wireless network100 described with respect to FIG. 3.

The method begins at step 412, where the user equipment receives networkassistance information from a network node. For example, wireless device110 may receive network assistance information from core network node320. The network assistance information is for assisting the wirelessdevice in performing OTDOA.

In particular embodiments, the network assistance information comprises:a list of reference cells; a list of neighbor cells; and a rule forterminating Reference Signal Time Difference (RSTD) measurements. Insome embodiments, the network assistance information includes any of theassistance information according to any of the embodiments and examplesabove.

At step 414, the user equipment performs RSTD measurement between a cellin the reference cell list and a cell in the neighbor cell list. Forexample, wireless device 110 may calculate a time of arrival (TOA) for areference signal from a reference cell, such a cell 115 a, and maycalculate a time of arrival (TOA) for a reference signal from a neighborcell, such as cell 115 b. Wireless device may determine a referencesignal time difference between the two measurements.

In some embodiments, the method continues to step 416, where the userequipment determines an RSTD quality of the measured RSTD. For example,wireless device 110 may measure an SINR of the reference signal as −10dB. In some embodiments, the measurements include any of themeasurements described with respect to any of the embodiments andexamples above.

At step 418, the user equipment determines whether the RSTD measurementsatisfies the rule for terminating RSTD measurements. For example, therule may require three positioning measurements with an SINR above −12dB. The UE determines whether the most recent measurement from steps 414and 416 satisfy the rule. If so, the method continues to step 420,otherwise the method returns to step 414.

In particular embodiments, the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least apre-determined number (N) of RSTD measurements having a least apre-determined quality (X). Some embodiments may include multiplecriteria. For example, in some embodiments the rule for terminating RSTDmeasurements indicates terminating RSTD measurements after taking atleast a first pre-determined number (N1) of RSTD measurements having aleast a first pre-determined quality (X1) or at least a secondpre-determined number (N2) of RSTD measurements having a least a secondpre-determined quality (X2) (e.g., three measurements of a lowerquality, or two measurements of a higher quality). In some embodiments,the determination is made according to any of the embodiments andexamples above.

At step 420, the user equipment the RSTD measurements to the networknode. For example, wireless device 110 may report RSTD measurements(e.g., the measurements from any previous iterations of step 414) tonetwork node 320. Network node 320 may use the measurements formultilateration calculations in determining a position of wirelessdevice 110. The report may include a quality of the RSTD measurements.

In some embodiments, the method includes step 422, where the userequipment also reports that the rule for terminating RSTD measurementswas satisfied. For example, wireless device 110 may indicate that themeasurement report is being sent early based on satisfaction of therule, and may specify the rule used. The information may be included inLug same report as in the previous step. In some embodiments, the reportincludes any suitable information according to any of the embodimentsand examples above.

Modifications, additions, or omissions may be made to method 400illustrated in FIG. 4. Additionally, one or more steps in method 400 maybe performed in parallel or in any suitable order.

FIG. 5 is a flow diagram of an example method in a network node,according to some embodiments. Method 500 includes steps for providingnetwork assistance for positioning measurements. In particularembodiments, one or more steps of FIG. 5 may be performed by networknode 320 of wireless network 100 described with respect to FIG. 3.

The method begins at step 512, where the network node transmits networkassistance information to a wireless device. The network assistanceinformation is for assisting the wireless device in performing OTDOA.For example, network node 320 transmits network assistance informationto wireless device 110.

In particular embodiments, the network assistance information comprisesa list of reference cells, a list of neighbor cells, and a rule forterminating RSTD measurements. The assistance information may includeany of the assistance information described above with respect to FIG.4.

At step 514, the network node receives a report that provides the RSTDmeasurements from the wireless device. For example, network node 320 mayreceive a report from wireless device 110. The report may include any ofthe information described above with respect to FIG. 4.

Modifications, additions, or omissions may be made to method 500illustrated in FIG. 5, Additionally, one or more steps in method 500 maybe performed in parallel or in any suitable order.

FIG. 6A is a block diagram illustrating an example embodiment of awireless device. The wireless device is an example of the wirelessdevices 110 illustrated in FIG. 3. In particular embodiments, thewireless device is capable of receiving network assistance informationfrom a network node; and performing RSTD measurement between a cell in areference cell list and a cell in a neighbor cell list. Upon determiningthe RSTD measurement satisfies the rule for terminating RSTDmeasurements, the wireless device is capable of reporting the RSTDmeasurements to the network node. Upon determining the RSTD measurementdoes not satisfy the rule for terminating RSTD measurements, thewireless device is capable of performing another RSTD measurementbetween the cell in the reference cell list and a cell in the neighborcell list.

Particular examples of a wireless device include a mobile phone, a smartphone, a PDA (Personal Digital Assistant), a portable computer (e.g.,laptop, tablet), a sensor, a modem, a machine type (MTC) device/machineto machine (M2M) device, laptop embedded equipment (LEE), laptop mountedequipment (LME), USB dongles, a device-to-device capable device, avehicle-to-vehicle device, or any other device that can provide wirelesscommunication. The wireless device includes transceiver 1110, processingcircuitry 1120, memory 1130, and power source 1140. In some embodiments,transceiver 1110 facilitates transmitting wireless signals to andreceiving wireless signals from wireless network node 120 (e.g., via anantenna), processing circuitry 1120 executes instructions to providesome or all of the functionality described herein as provided by thewireless device, and memory 1130 stores the instructions executed byprocessing circuitry 1120. Power source 1140 supplies electrical powerto one or more of the components of wireless device 110, such astransceiver 1110, processing circuitry 1120, and/or memory 1130.

Processing circuitry 1120 includes any suitable combination of hardwareand software implemented in one or more integrated circuits or modulesto execute instructions and manipulate data to perform some or all ofthe described functions of the wireless device. In some embodiments,processing circuitry 1120 may include, for example, one or morecomputers, one more programmable logic devices, one or more centralprocessing units (CPUs), one or more microprocessors, one or moreapplications, and/or other logic, and/or any suitable combination of thepreceding. Processing circuitry 1120 may include analog and/or digitalcircuitry configured to perform some or all of the described functionsof wireless device 110. For example, processing circuitry 1120 mayinclude resistors, capacitors, inductors, transistors, diodes, and/orany other suitable circuit components.

Memory 1130 is generally operable to store computer executable code anddata. Examples of memory 1130 include computer memory (e.g., RandomAccess Memory (RAM) or Read Only Memory (ROM)), mass storage media(e.g., a hard disk), removable storage media (e.g., a Compact Disk (CD)or a Digital Video Disk (DVD)), and/or or any other volatile ornon-volatile, non-transitory computer-readable and/orcomputer-executable memory devices that store information.

Power source 1140 is generally operable to supply electrical power tothe components of wireless device 110. Power source 1140 may include anysuitable type of battery, such as lithium-ion, lithium-air, lithiumpolymer, nickel cadmium, nickel metal hydride, or any other suitabletype of battery for supplying power to a wireless device.

Other embodiments of the wireless device may include additionalcomponents (beyond those shown in FIG. 6A) responsible for providingcertain aspects of the wireless device's functionality, including any ofthe functionality described above and/or any additional functionality(including any functionality necessary to support the solution describedabove).

FIG. 6B is a block diagram illustrating example components of wirelessdevice 110. The components may include receiving module 1150, measuringmodule 1152, and reporting module 1154.

Receiving module 1150 may perform the receiving functions of wirelessdevice 110. For example, receiving module 1150 may receive, from anetwork node, network assistance information described in any of theembodiments or examples above (e.g., step 412 of FIG. 4). In certainembodiments, receiving module 1150 may include or be included inprocessing circuitry 1120. In particular embodiments, receiving module1150 may communicate with measuring module 1152 and reporting module1154.

Measuring module 1152 may perform the measuring functions of wirelessdevice 110. For example, measuring module 1152 may measure positioningreference signals according to any of the embodiments or examples above(e.g., steps 414 and 416 of FIG. 4). In certain embodiments, measuringmodule 1152 may include or be included in processing circuitry 1120. Inparticular embodiments, measuring module 1152 may communicate withreceiving module 1152 and reporting module 1154.

Reporting module 1154 may perform the reporting functions of wirelessdevice 110. For example, reporting module 1154 may report measurementreports to a network node according to any of the examples describedabove (e.g., steps 420 and 422 in FIG. 4). In certain embodiments,reporting module 1154 may include or be included in processing circuitry1120. In particular embodiments, reporting module 1154 may communicatewith receiving module 1150 and measuring module 1152.

FIG. 7 is a block diagram illustrating an example embodiment of anetwork node. The network node is an example of the network node 120illustrated in FIG. 3. Network node 120 can be an eNodeB, a nodeB, abase station, a wireless access point (e.g., a Wi-Fi access point), alow power node, a base transceiver station (BTS), a transmission pointor node, a remote RF unit (RRU), a remote radio head (RRH), or otherradio access node. The network node includes at least one transceiver1210, at least one processing circuitry 1220, at least one memory 1230,and at least one network interface 1240. Transceiver 1210 facilitatestransmitting wireless signals to and receiving wireless signals from awireless device, such as wireless devices 110 (e.g., via an antenna);processing circuitry 1220 executes instructions to provide some or allof the functionality described above as being provided by a network node120; memory 1230 stores the instructions executed by processingcircuitry 1220; and network interface 1240 communicates signals tobackend network components, such as a gateway, switch, router, Internet,Public Switched Telephone Network (PSTN), controller, and/or othernetwork nodes 120. Processing circuitry 1220 and memory 1230 can be ofthe same types as described with respect to processing circuitry 1120and memory 1130 of FIG. 6A above.

In some embodiments, network interface 1240 is communicatively coupledto processing circuitry 1220 and refers to any suitable device operableto receive input for network node 120, send output from network node120, perform suitable processing of the input or output or both,communicate to other devices, or any combination of the preceding.Network interface 1240 includes appropriate hardware (e.g., port, modem,network interface card, etc.) and software, including protocolconversion and data processing capabilities, to communicate through anetwork.

Other embodiments of network node 120 include additional components(beyond those shown in FIG. 7) responsible for providing certain aspectsof the network node's functionality, including any of the functionalitydescribed above and/or any additional functionality (including anyfunctionality necessary to support the solution described above). Thevarious different types of network nodes may include components havingthe same physical hardware but configured (e.g., via programming) tosupport different radio access technologies, or may represent partly orentirely different physical components.

FIG. 8A is a block schematic of an example core network node 320, inaccordance with certain embodiments. In particular embodiments, the corenetwork node is capable of transmitting network assistance informationto a wireless device, and receiving a report that provides the RSTDmeasurements from the wireless device.

Examples of core network nodes can include an Evolved Serving MobileLocation Centre (E-SMLC), a mobile switching center (MSC), a servingGPRS support node (SGSN), a mobility management entity (MME), a radionetwork controller (RNC), a base station controller (BSC), an access andmobility management function (AMF), and so on. The core network nodeincludes processing circuitry 620, memory 630, and network interface640. In some embodiments, processing circuitry 620 executes instructionsto provide some or all of the functionality described above as beingprovided by the network node, memory 630 stores the instructionsexecuted by processing circuitry 620, and network interface 640communicates signals to any suitable node, such as a gateway, switch,router, Internet, Public Switched Telephone Network (PSTN), networknodes 120, radio network controllers or core network nodes 320, etc.

Processing circuitry 620 may include any suitable combination ofhardware and software implemented in one or more modules to executeinstructions and manipulate data to perform some or all of the describedfunctions of the core network node. In some embodiments, processingcircuitry 620 may include, for example, one or more computers, one ormore central processing units (CPUs), one or more microprocessors, oneor more applications, and/or other logic.

Memory 630 is generally operable to store instructions, such as acomputer program, software, an application including one or more oflogic, rules, algorithms, code, tables, etc. and/or other instructionscapable of being executed by a processor. Examples of memory 630 includecomputer memory (for example, Random Access Memory (RAM) or Read OnlyMemory (ROM)), mass storage media (for example, a hard disk), removablestorage media (for example, a Compact Disk (CD) or a Digital Video Disk(DVD)), and/or or any other volatile or non-volatile, non-transitorycomputer-readable and/or computer-executable memory devices that storeinformation.

In some embodiments, network interface 640 is communicatively coupled toprocessing circuitry 620 and may refer to any suitable device operableto receive input for the network node, send output from the networknode, perform suitable processing of the input or output or both,communicate to other devices, or any combination of the preceding.Network interface 640 may include appropriate hardware (e.g., port,modem, network interface card, etc.) and software, including protocolconversion and data processing capabilities, to communicate through anetwork.

Other embodiments of the network node may include additional componentsbeyond those shown in FIG. 8A that may be responsible for providingcertain aspects of the core network node's functionality, including anyof the functionality described above and/or any additional functionality(including any functionality necessary to support the solution describedabove).

FIG. 8B is a block diagram illustrating example components of corenetwork node 320. The components may include receiving module 650 andtransmitting module 652.

Receiving module 650 may perform the receiving functions of core networknode 320. For example, receiving module 650 may receive a measurementreport as described in any of the embodiments or examples above (e.g.,step 514 of FIG. 5). In certain embodiments, receiving module 650 mayinclude or be included in processing circuitry 620. In particularembodiments, receiving module 650 may communicate with transmittingmodule 652.

Transmitting module 652 may perform the transmitting functions of corenetwork node 320. For example, transmitting module 652 may send networkassistance information for location measurements to a wireless deviceaccording to any of the examples described above (e.g., step 512 of FIG.5). In certain embodiments, transmitting module 652 may include or beincluded in processing circuitry 620. In particular embodiments,transmitting module 652 may communicate with receiving module 650.

Some embodiments of the disclosure may provide one or more technicaladvantages. Some embodiments may benefit from some, none, or all ofthese advantages. Other technical advantages may be readily ascertainedby one of ordinary skill in the art. For example, some embodimentsassist a wireless device to terminate a RSTD measurement after thewireless device performs enough measurements. An another example,certain embodiments avoid unnecessary measurements by the wirelessdevice. As another example, certain embodiments minimize the processingeffort and power consumption at the device side. As yet another example,certain embodiments reduce the overall overheard of OTDOA positioningmethod for IoT devices. As a further example, certain embodiments addconfigurability at the location server to trade-off between positioningaccuracy and IoT device power consumption, e.g., because some deviceshave low positioning accuracy requirements. As a final example, certainembodiments add the configurability to trade-off between time-to-fix andpositioning accuracy, a more restrictive termination criterion will leadto a shorter time-to-fix.

Although this disclosure has been described in terms of certainembodiments, alterations and permutations of the embodiments will beapparent to those skilled in the art. Although some embodiments havebeen described with reference to certain radio access technologies, anysuitable radio access technology (RAT) or combination of radio accesstechnologies may be used, such as long term evolution (LTE),LTE-Advanced, NR, UMTS, HSPA, GSM, cdma2000, WiMax, WiFi, etc.Accordingly, the above description of the embodiments does not constrainthis disclosure. Other changes, substitutions, and alterations arepossible without departing from the spirit and scope of this disclosure.

The following examples are examples of how certain aspects of theembodiments described herein could be implemented within the frameworkof a specific communication standard. In particular, the followingexamples provide a non-limiting example of how the embodiments describedherein could be implemented within the framework of a 3GPP RAN standard.The changes described by the examples are merely intended to illustratehow certain aspects of the embodiments could be implemented in aparticular standard. However, the embodiments could also be implementedin other suitable manners, both in the 3GPP Specification and in otherspecifications or standards.

An objective of the Rel. 14 NB-IoT enhancements is to improve thepositioning support based on OTDOA. In some examples, baseline signal(s)include NB-IoT Rel-13 signals and LTE CRS/PRS in 1 PRB. NB-IoTpositioning reference signal resource pattern in one subframe is atleast LTE PRS in 1 PRB. NB-IoT PRS do not occur in a subframe containingNPDCCH, NPDSCH, NPBCH or NPSS/NSSS. Some examples include: PSD boostingof NPRS symbols; configuration of time resources for NPRS; indication ofexact subframes is by: Part A: A bitmap on subframes which are notNB-IoT DL subframes (i.e. invalid DL subframes). Bitmap is a fixedlength of 10 bits, is the same length as valid subframe configuration,i.e. 10 bits or 40 bits, or is a fixed length of x bits (e.g., x=20).Part B: Indicated with one start subframe, one periodicity, and onenumber of repetitions for the occasions. Indication of exact subframe onan anchor carrier or non-anchor carrier may use Part A and/or Part B. Anindication of NPRS muting patterns may be indicated with a periodic NPRSmuting sequence.

Particular examples acknowledge the advantage of OTDOA in maintainingthe current signaling and architecture as legacy, and some examplesrefine them for better applicability for NB-IoT.

One advantage in considering the OTDOA method as the positioning methodcandidate for NB-IoT is that UEs keep the legacy signaling frameworkprocedure for these devices. Providing OTDOA network assistanceinformation can be useful for NB-IoT devices considering the limitedcapability and power consumption that these devices have. However, thecontent of this signaling should be different and tailored to thecapabilities and requirements of these UEs. Also, minimizing the size ofthe signaling makes it scalable to NB-IoT limited capabilities. Beloware some examples of network assistance information for providingimproved positioning performance for these devices.

NB-IoT UEs are expected to have very low capabilities and some minimumrequirements such as the sampling rate, bandwidth, supported coverageclass, etc. may already be known to the network. Therefore, it is powerefficient to omit or limit the UE capability signaling for NB-IoT.

If the NB-IoT UE has some advanced capability in terms of for example“higher sampling rate” from the standard NB-IoT, the UE can inform thelocation server in terms of this capability to receive more tailoredassistance information from the network according to the specified UEcapability.

Another parameter can be the capability of supporting theinter-frequency measurement by the device, this would be also requiredfor the network in providing assistance neighbor cell information, etc.

While there may exist more parameters that can be useful for the networkto know about the UE, NB-IoT should require minimum amount of OTDOAsignaling for positioning estimation.

Observation 1: NB-IoT should require minimum amount of OTDOA signalingfor positioning estimation.

Proposal 1: UE capabilities can be optionally sent to the locationserver without any explicit request from the network for thisinformation.

Proposal 2: UE capability in supporting inter-frequency measurementshould be signaled to the location server in order to activate thisfeature.

Proposal 3: Inter-frequency measurements can be supported for NB-IoTUEs.

A location server (i.e. E-SMLC) may provide the NB-IoT UE with a list ofpotential reference cell and neighbor cells to be used for RSTDmeasurements. For each of these lists, the E-SMLC provides a set ofinformation including the physical cell ID, the global cell ID and thePRS info, etc. Other information is the expected RSTD measurement andthe expected RSTD uncertainty measurement, which can be useful at theUE. One parameter to be considered is that NB-IoT UEs should aggregatethe downlink reference signal (e.g., PRS) for several/many occasions(repetitions), to achieve an acceptable positioning estimation. Whilethis would also impact the response time, it is important that thenetwork assist the UE for an optimum performance in terms of theresponse time. This assistance intends to minimize the complexity andpower consumption at the UE side.

In the legacy procedure, the UE reports 15 RSTDs assuming that the SINRis above threshold. To further assist the NB-IoT UEs, and to avoidunnecessary measurement at the UE, the location server can provide theUE with the option that if N RSTDs with quality X have been measured,then the UE is allowed to report the RSTD measurement, and do notcontinue with further measurements. N & X can be configured asmeasurement instruction. For example, it may be sufficient to have 10RSTDs with SINR above threshold. On the other hand, if there are 4 cellswith high SINR, it is still possible to have a position estimation forthe UE.

Observation 2: To avoid unnecessary measurement at the UE, the locationserver can provide the NB-IoT UE with more conditional time of response,and number of required RSTD measurements.

Proposal 4: The location server can provide the UE with the option thatif N RSTDs with quality X have been measured, then the UE is allowed toreport the RSTD measurement, and do not continue with furthermeasurements. Example: (N, X)={(12, −14 dB), (10, −13 dB), (8, −12 dB),(6, −11 dB), (5, −10 dB)}

The NB-IoT UE performs RSTD measurements based on the assistedinformation sent by the E-SMLC. The UE may report both the RSTD and RSTDquality to the E-SMLC. The RSTD quality is according to the estimatedRSTD measurement sent by the location server. In case the UE hasterminated the RSTD measurement procedure according to one of theconditional termination criteria sent by the network as the assisteddata, the NB-IoT can optionally report the condition used together withthe RSTD measurements.

Proposal 5: The NB-IoT UE shall optionally report the network in termsof termination condition choice for RSTD measurement together withsending the RSTD measurements.

Abbreviations:

-   3GPP 3rd Generation Partnership Project-   ACB Access Class Barring-   AS Access Stratum-   CA Carrier Aggregation-   CC Component Carrier-   CN Core Network-   eNB Evolved Node B-   eNodeB Evolved Node B-   E-SMLC Evolved Serving Mobile Location Center-   FeMTC Further enhanced MTC-   FDD Frequency Division Duplex-   GNSS Global Navigation Satellite System-   ID Identifier-   IoT Internet of Things-   LPP LTE Positioning Protocol-   LTE Long-Term Evolution-   MME Mobility Management Entity-   MSC Mobile Switching Center-   MTC Machine Type Communication-   NAS Non Access Stratum-   NB-IoT NarrowBand-IoT-   NR New Radio-   NW Network-   OTDOA Observed Time Difference of Arrival-   PCC Primary Component Carrier-   PCell Primary Cell-   PDU Protocol Data Unit-   PGW Packet Data Network Gateway-   PRB Physical Resource Block-   RAT Radio Access Technology-   RAN Radio Access Network-   RRC Radio Resource Control-   RSRP Reference Signal Received Power-   RSRQ Reference Signal Received Quality-   RSTD Reference Signal Time Difference-   SCC Secondary Component Carrier-   SCell Secondary Cell-   SGW Serving Gateway-   SLA Service Level Agreement-   SRB Signaling Radio Bearer-   TDD Time Division Duplex-   TDOA Time Difference Of Arrival-   TOA Time Of Arrival-   UE User Equipment-   UMTS Universal Mobile Telecommunications System-   UTDOA Uplink Time Difference of Arrival

The invention claimed is:
 1. A method for use in a network node ofproviding network assistance for positioning measurements, the methodcomprising: transmitting network assistance information to a wirelessdevice, the network assistance information forassisting the wirelessdevice in performing Observed Time Difference Of Arrival (OTDOA), thenetwork assistance information comprising: a list of reference cells; alist of neighbor cells; a rule for terminating Reference Signal TimeDifference (RSTD) measurements; and receiving a report that provides theRSTD measurements from the wireless device; wherein the rule forterminating the RSTD measurements indicates terminating the RSTDmeasurements after taking at least a pre-determined number (N) of RSTDmeasurements having a least a pre-determined quality (X).
 2. The methodof claim 1, wherein the pre-determined number (N) is less than fifteen.3. The method of claim 1, wherein the report includes a quality of theRSTD measurements.
 4. The method of claim 1, wherein the report includesan indication that the rule for terminating RSTD measurements wassatisfied.
 5. The method of claim 1, wherein the rule for terminatingRSTD measurements indicates terminating RSTD measurements after takingat least a first pre-determined number (N1) of RSTD measurements havinga least a first pre-determined quality (X1) or at least a secondpre-determined number (N2) of RSTD measurements having a least a secondpre-determined quality (X2).
 6. A network node capable of providingnetwork assistance for positioning measurements, the network nodecomprising processing circuitry operable to: transmit network assistanceinformation to a wireless device, the network assistance information forassisting the wireless device in performing Observed Time Difference OfArrival (OTDOA), the network assistance information comprising: a listof reference cells; a list of neighbor cells; a rule for terminatingReference Signal Time Difference (RSTD) measurements; and receive areport that provides the RSTD measurements from the wireless device;wherein the rule for terminating the RSTD measurements indicatesterminating the RSTD measurements after taking at least a pre-determinednumber (N) of RSTD measurements having a least a pre-determined quality(X).
 7. The network node of claim 6, wherein the pre-determined number(N) is less than fifteen.
 8. The network node of claim 6, wherein thereport includes a quality of the RSTD measurements.
 9. The network nodeof claim 6, wherein the report includes an indication of whether therule for terminating RSTD measurements was satisfied.
 10. The networknode of claim 6, wherein the rule for terminating RSTD measurementsindicates terminating RSTD measurements after taking at least a firstpre-determined number (N1) of RSTD measurements having a least a firstpre-determined quality (X1) or at least a second pre-determined number(N2) of RSTD measurements having a least a second pre-determined quality(X2).